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TREMEC Stick Shift Shootout stalwart Jeff Smith TKX-swapped his latest Fox Mustang

Posted By: Evan J. Smith
Stick-Shift Mood
TREMEC Stick Shift Shootout stalwart Jeff Smith TKX-swapped his latest Fox Mustang
Written by Steve Turner
Photography by Patrick Hill and courtesy of TREMEC
For some, rowing the gears is the only way to fly. That is the mantra of Jeff Smith. Known as the Stick Shift Dude on social media, he is a regular in stick-shift racing across the Southeast, including consistent appearances in the TREMEC Stick Shift Shootout a several Holley NMRA Ford Nationals events.
Recently, Smith went back to his roots and picked up a Fox Mustang to serve as a fun street car and a companion to his notable 2004 SVT Mustang Cobra, known as The Pumpkin in deference to its Competition Orange exterior motif.
“I’ve always owned Fox-bodies. I sold one 13 years ago to buy my 04 Cobra, but now I'm better off financially, so I was surfing the Fox-body marketplace and stumbled across this SSP coupe so I bought I,” Smith explained. “Fox bodies are the next ’69 Camaros in my opinion.”
You would assume that someone so associated with third-pedal machines would only consider purchasing rides that are so-equipped from the factory. However, when it comes to finding Fox Mustangs in good condition for a favorable price, some compromises are necessary.
“When you find a car that’s decent and not botched up, it doesn’t matter if it is an auto or a stick,” Smith said. “I’ve always used TREMEC transmissions with success, so the plan was always to swap it! Autos seem to be cheaper, but I also prefer them because they usually aren’t as abused.”
With the car in his driveway, Smith couldn’t wait to put in a manual transmission, but the question remained as to which transmission to install. Having vast experience with a wide range of TREMEC offerings, he opted to go with the company’s latest five-speed gearbox.
“I’ve owned TKO 3550s, TKO 600s, and Magnums, but I never owned a TKX and Mike Kidd told me it was the ticket so I took his advice and I love it,” Smith said.
If you aren’t familiar with the TREMEC TKX, it is the company’s fresh take on the five-speed manual, and it is geared toward swaps into high-performance machines. Not only is it rugged, but it is compact enough to fit it tight transmission tunnels.
“The TKX is a new design that is the result of listening to our customers’ wants and needs for a five-speed capable of 600 lb-ft that shifts at higher rpm, but in a smaller package allowing them to install the TKX in multiple applications with little to no modifications to their vehicle’s tunnel,” Mike Kidd, Aftermarket Business Unit Manager at TREMEC, explained.
After its debut in the fall of 2020, the TKX was an instant hit. Heeding those market demands paid off and the rugged, high-revving manual quickly became the go-to swap transmission, especially for applications with limited tunnel space.
“It’s what the industry was missing — a five-speed capable of higher-rpm shifts in a smaller package,” Kidd enthused. “We sold more transmissions in the first 12 months than any other TREMEC aftermarket transmission in history.”
When it comes to Fox Mustangs like Smith’s latest acquisition the compact-sized and durable constitution of the TKX makes it an ideal replacement for the factory automatic or even the light-duty factory manual option. 
“Although the Fox-body came with a T-5 as a manual option, it’s only rated at 300 lb-ft, which was great for that time in the industry,” Kidd explained. “However, our customers are adding more and more power upgrades and the TKX (rated at 600 lb-ft) allows them to keep their car a manual without a lot of additional modifications for fitment.”
After researching what the swap required, Smith picked up the necessary support hardware from the likes of Driveshaft Shop, Late Model Restoration, McLeod Racing, Steeda, Stifflers, and Total Mustang Performance. With the parts in hand, he turned to a shop in Oviedo, Florida to handle the conversion, and you can see the highlights of the installation in our photos here.
“I had Knights Automotive handle the swap, and they made it look easy. It took about five hours with two skilled technicians doing the work, then I was driving off,” Smith said.
With the TKX swap complete and the factory slushbox in the rearview window, this Fox’s fun-to-drive factory revved up. Moreover, its driver felt more at home with three pedals on the floor.
“Obviously the automatic wasn’t very fun, and it made the car feel more or like basic transportation,” Smith said. “The five-speed keeps me busy and more in tune with the overall driving experience.”
With the Fox more fun to drive, Smith won’t be replacing his 9-second Terminator at the racetrack, but there is a chance he could bring the car out to run at the season opener at Orlando Speed World in March. If he does bring it out, it will be ready for competition thanks to its new gearbox.
“The new design with wider gears and multi-cone synchronizers is capable of shifts upwards of 7800 rpm, which makes it a great candidate for cruising the streets or taking it to the strip for a weekend of fun competing in a True Street event,” Kidd said. “Fun fact: The winner of the final NMRA TREMEC Stick Shift Shootout for 2022 was a Fox-body equipped with a TKX.”


Jeff Smith picked up this nearly stock 1988 Mustang LX coupe as a daily driver. There was only one problem, in his estimation, with this ex-government ride — it had an automatic transmission in the tunnel. 

For the noted manual-transmission racer, the remedy was obvious. He set out to swap in a manual transmission, but not just any manual transmission. He chose TREMEC’s TKX five-speed, which will withstand 600 lb-ft of torque and shift as high as 7,800 rpm. Those attributes and its compact size make the TKX an ideal manual-swap option for a host of performance cars. The TKX carries a dry weight of just 99 pounds, which isn’t much more than a T-5, but far less than a 150-plus-pound AOD.

Along with the new transmission, Smith opted for a new aluminum driveshaft from The Driveshaft Shop. Not only does the new shaft reduce rotating mass, but it delivers more strength and it is high-speed balanced for vibration-free operation. 

To execute the swap, Smith ordered the 1979-93 Mustang Manual Transmission Hump Kit from Late Model Restoration. It includes a steel manual transmission tunnel, ½-inch rivets, lower shift boot, shift-boot retaining bolts, and shift-boot retainer J-nuts. The crew at Knights Automotive modified the tunnel for the hump using it as a template. 

Moving from an automatic to a manual required a move from a flexplate to a flywheel, and Smith chose a billet aluminum unit from McLeod to go with his new clutch.

With the flywheel torqued in place, the Knights Automotive team bolted up the new McLeod single-disc clutch. 

Next, they prepped the manual bellhousing with a new clutch fork pivot followed by the new clutch fork and throwout bearing.

Installing the new bellhousing paves the way to easily bolt up the TKX. Since this car is a daily driver, a factory-style housing is just fine. However, if you plan to regularly race a car with a TKX, an SFI-approved, blow-proof unit ensures safety and legality at the racetrack. 

Two technicians breezed through the installation and two people makes lifting the new transmission into place, navigating the input shaft into place, and bolting the gearbox to the bellhousing much easier. 

To secure the rear of the transmission, Smith opted for this robust transmission mount and driveshaft safety loop from Stifflers. The single-tube design utilizes the factory mounting points and maintains the factory pinion angle. Meanwhile, the Stifflers bolt-on driveshaft safety loop is designed to exceed NHRA safety standards. 

A crucial part of this swap is replacing the factory automatic pedal box with a manual-transmission arrangement. These parts have yet to be reproduced in the aftermarket, so Smith sourced a used manual pedal setup from Total Mustang Performance.

The factory clutch quadrant is fragile and lacks adjustability, so Smith went with a McLeod billet adjustable unit that is durable and allows for dialing in the optimal clutch engagement settings.

With the new transmission installed, Knights Automotive bolted on the lower boot from LMR to seal the interior from the elements. 

In addition to the necessary swap parts from the 1979-93 Mustang Manual Transmission Hump Kit, Smith also picked up one of LMR’s 1987-93 Mustang Cup Holder Center Console Panel with two USB ports. This addition rounds out the installation nicely.

To wrap up the installation, Knights Automotive installed a Steeda shifter handle and a shift knob from LMR. The TREMEC TKX five-speed transmission looks right at home in Smith’s daily driver.

With an essentially stock, pushrod 5.0-liter under the hood, Smith’s Fox coupe won’t push the envelope of the TKX’s 600 lb-ft capacity, but it offers plenty of room to grow as the mods keep rolling. 
The Driveshaft Shop
(800) 564-2244
Knights Automotive
(407) 542-5669
Late Model Restoration
(866) 507-3786
McLeod Racing
(714) 630-2764
(800) 950-0774
(317) 837-2444
(800) 401-9866

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